• Journal of People, Plants, and Environment
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• v.23 no.3
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• pp.347-362
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• 2020

Background and objective: It is difficult to conclusively determine the exact cause of tree defects since multiple causes are involved such as climate change, plantation, tree quality and planting time, construction, planting base, drainage, sunshine conditions, maintenance, and microclimate. The data related to landscaping construction defects are scattered or fragmented by companies and years, but not managed systematically by the defect information management system. Most of the earlier studies associated with tree defects in apartment complexes suggested defect rates after examining tree defects in the completed construction site and proposed fragmentary and subjective conclusions about the causes of defects observed in trees with high defect rates. It is proposed to continue to conduct studies on the establishment and analysis of systematic databases to identify the exact causes of tree defects and measures to improve, and the need to accumulate systematic data in the construction process where many defects arises. This study was conducted to reduce the defects of trees planted in apartment complexes. Methods: Main factors related to tree defects were subdivided based on the results of literature review and a defect investigation at the completion site, and tree history management items were selected and subdivided during the construction stage. Results: The criteria for the preparation of subdivided items were obtained, and the tree history management checklist was written for the site under actual construction and a systematic database was established. Items that are categorized based to the causes of defects include the location of nurseries, date, tree quality, site conditions, planting techniques, microclimates, and maintenance. Conclusion: This study suggested tree history management items based on the tree defects that can be identified at the construction stage and applied them to the selected study site, which differentiates this study from earlier studies. It will be necessary to conduct a comprehensive and objective time series analysis on tree defects that occur over time by continuously monitoring and collecting data after construction.

• Journal of the Korean housing association
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• v.22 no.4
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• pp.83-92
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• 2011

Apartment is settled down as a main housing type and massive supply has been conducted since 1990's. The government has focused on the housing supply to improve the housing number and cut its price. On the contrary, the management of the housing has been neglected to get an early deterioration. Since 1995's, various ways have been made to improve and maintain the building function and performance. Among these, the long-term repair plan has played a main role to manage the housing condition and plan the repair schedule for preparing the massive cost of repair such as a roof proof, elevator change. The long-tern repair plan provides the repair time and repair rate according to various construction types. Most of the management agent apply the repair standard into the field area. But the repair time could not reflect the present condition and bring into the wrong maintenance. Therefore, the repair time for the long-term maintenance plan would be revised and reflected from the material and technology development. |n this study, it aimed at improvement for the repair time in various construction types which are provided in the long-term repair plan. For this, the 22 management agents are surveyed directly. This study shows that the repair time of the painting are correspondent to the repair time of the long-term plan irregardless of the painting materials. Most of other areas would correspondently similar to the long-term plan. This study could not include the building location, material and other haracteristics. Therefore, the further study would be needed to reflect the building and materials attributes to get the detailed repair time.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.855-866
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• 2023

With the rapid advancement and sophistication of defense weapon systems, the government, military, and the defense industry have conducted various innovative attempts to improve the efficiency of post-logistics support(PLS). The Ministry of Defense has mandated RAM-C(Reliability, Availability, and Maintainability-Cost) analysis as a requirement according to revised Total Life Cycle System Management Code of Practice in May 2022. Especially, for the project budget forecast of new PBL(Performance Based Logistics) business contacts, RAM-C is recognized as an obligatory factor. However, relevant entities have not officially provided guidelines or manuals for RAM-C analysis, and each defense contractor conducts RAM-C analysis with different standards and methods to win PBL-related business contract. Hence, this study aims to contribute to the generalization of the analysis procedure by presenting a cost analysis case based on RAM-C for the supply of military depot maintenance PBL project. This study presents formulas and procedures to determine requirements of military depot maintenance PBL project for repair parts supply. Moreover, a sensitivity analysis was conducted to find the optimal cost/utilization ratio. During the process, a correlation was found between supply delay and total cost of ownership as well as between cost variability and utilization rate. The analysis results are expected to provide an important basis for the conceptualization of the cost analysis for the supply of military depot maintenance PBL project and are capable of proposing the optimal utilization rate in relation to cost.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.432-437
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• 2004

In this study, Pavement Management System(PMS) was developed to overcome the unscientific pavement management limitations of the past. PMS program is economic, efficient and scientific. Also, it produces the best maintenance method through exact judgement and logical analysis of pavement condition. First of all, the logical algorithm, that is such as investigation and analysis of pavement, detailed naked eye investigation and the estimation for whole system etc., was composed on the basis of the domestic and the outside data on PMS and pavement condition data of Seoul metropolitan. And then it was verified that this algorithm is suitable through the research examples of PMS data and the results of detailed naked eye investigation. Also, Geographic Information System(GIS) was integrated on PMS program. Therefore, PMS program was developed so as to use easily on the basis of the logical algorithm.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.50-59
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• 2021

The need for risk based safety management has been highlighted in accordance with the growth of aviation industry and public interest in aviation safety. Maintenance, Repair and Overhaul (MRO) in aviation industry is defined to guarantee the safety and reliability. Therefore, state's Civil Airworthiness Authority (CAA) has established safety oversight system dedicated for the development of a healthy MRO industry. The study proposed a risk based oversight system considering Korean environment. Based on literature review including analysis of International Civil Aviation Organization guidance and advance system, we identified two organization risks. Organization complexity can be evaluated in accordance with how large the organization is and how complicated the service they provide are. Organization profile is the organization's characteristic related with safety. This study contributes to improving the process of identifying risk of organization and focusing surveillance capabilities on risk areas for efficient management of CAA's resources.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1364-1371
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• 2011

Advanced EMU completed a production of test train, composed of 6 cars, after 5 years of development process, and it is currently under the process of integrated test and evaluation to inspect performance of car system, efficiency of transport, safety, punctuality, energy efficiency in accordance with urban railways act at Daebul test line. Advanced EMU was produced under consideration of transportation capacity, maintainability, reliability, energy saving, convenience of passengers, and traffic-vulnerables, so it has an epochal difference from former EMU system. And advanced EMU assures operation management from manager's perspective and efficiency of maintenance for practicalization of car and individual equipment. This paper introduces each major equipment of advanced EMU which is based on many years of experience of management and maintenance.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.2
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• pp.81-86
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• 2014

In this paper, a jointly optimal group replacement and spare provisioning policy is presented. Most maintenance policies assume that the spare inventory is always available, but in practice the maintenance schedule is affected by the availability of spare inventory. We present a maintenance-inventory model which jointly optimizes the group replacement interval and spare ordering quantity. Group replacement policy is used when a group of units are put in operation simultaneously. The operating fleet is replaced altogether at a predetermined number of units are failed. A sufficient level of spare inventory is carried to perform a number of group replacement. A cost rate expression which considers the group maintenance cost and inventory holding cost is derived and a heuristic method for searching the optimum value of decision variables is suggested. Numerical examples demonstrate the analytical results and the performance of the presented model.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.562-569
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• 2022

The alarm monitoring technology applied to existing operating ships manages data items such as temperature and pressure with AMS (Alarm Monitoring System) and provides an alarm to the crew should these sensing data exceed the normal level range. In addition, the maintenance of existing ships follows the Planned Maintenance System (PMS). whereby the sensing data measured from the equipment is monitored and if it surpasses the set range, maintenance is performed through an alarm, or the corresponding part is replaced in advance after being used for a certain period of time regardless of whether the target device has a malfunction or not. To secure the reliability and operational safety of ship engine operation, it is necessary to enable advanced diagnosis and prediction based on real-time condition monitoring data. To do so, comprehensive measurement of actual ship data, creation of a database, and implementation of a condition diagnosis monitoring system for condition-based predictive maintenance of auxiliary equipment and piping must take place. Furthermore, the system should enable management of auxiliary equipment and piping status information based on a responsive web, and be optimized for screen and resolution so that it can be accessed and used by various mobile devices such as smartphones as well as for viewing on a PC on board. This update cost is low, and the management method is easy. In this paper, we propose CBM (Condition Based Management) technology, for autonomous ships. This core technology is used to identify abnormal phenomena through state diagnosis and monitoring of pumps and purifiers among ship auxiliary equipment, and seawater and steam pipes among pipes. It is intended to provide performance diagnosis and failure prediction of ship auxiliary equipment and piping for convergence analysis, and to support preventive maintenance decision-making.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.311-314
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• 2001

The Military made an investment continuously in facilities construction since the Korea War but, a lot of Military-Facilities Construction have overlooked a long terms plan and detailed examination. The deteriorated facilities that becomes more than about 20 years of the military possession facilities is account about $25\%$ and these are real condition that is not achieving the function properly. Early Deterioration of Military-Facilities bring about waste of national defense cost, environmental pollution and so on. These are not very desirable for nations, societies and environment. Therefore, this study presented maintenance improvement of the Military Facilities for of a long life-cycle of Facilities

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.789-795
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• 2008

In recent, the rolling stocks are gradually complicated in respect with design and production to improve the safety and reliability. Also, the reliability centered maintenance corresponding with system specification or technical requirements is needed to meet the higher quality in railway service. In present, each railway authorities are collecting the failure's data using information system, applying those for maintenance works. However, this system has not established with systematic and scientific approach. This paper represents the existing activities and plans for RCM management system for AREX's EMU.